.banner {
    position: relative;
    width: 100%;
    max-width: 2000px;
    margin: auto;
}

.banner > img {
    width: 100%;
}

#bannerD {
    display: block;
}

#bannerM {
    display: none;
}

@media (max-width: 650px) {
    #bannerD {
        display: none;
    }

    #bannerM {
        display: block;
    }
}